A Vav Valve, or Variable Air Volume valve, is an HVAC (Heating, Ventilation and Air Conditioning) component that modulates air flow in response to a change in temperature. It regulates the amount of conditioned air being supplied to a space by varying the output of the main air handler. Vav valves are designed to improve indoor air quality, energy efficiency, and occupant comfort levels. They are typically installed in commercial facilities and can provide a significant reduction in energy costs over time.